This image to the right is a series of images taken in August and September 2010. A significant number of contrail observations in the sky of Buenos Aires led to documentary photography by The Sun Maker. The research of these photographs resulted in this article.

Contrails are clouds that appear in the sky. They are the result of condensation trails caused by the interaction of airplanes with the atmosphere. Sometimes we look up into the sky and see a straight thin clouded line. Sometimes we can even see a plane at its end. These condensation clouds are called condensation trails, otherwise known as contrails.

Water vapour, heat differences and vapour from the exhaust of the aircrafts create contrails. Military planes along with civilian planes are known to cause contrails. Flying at low altitudes, speed, sudden change and descend, manoeuvring, sudden rerouting, temperature and atmospheric conditions all influence contrails. An aircraft can also be identified by the contrail it has left in the sky.

Contrails should not be confused with sonic clouds, military flares or agricultural spraying. Unlike contrails, sonic clouds are a special kind of atmospheric alteration caused by supersonic airplanes that go over the speed of sound. On the other hand, military flares are countermeasure tools used in combat or mission training. Finally, agricultural spraying involves airplanes that spray pest control and other chemicals over crops.

Contrails are clearly different from other events. As this series of images shows: the image to the right shows a sonic cloud.

Image was taken somewhere over the Philippine Sea a US Navy (USN) F/A-18F Super Hornet, Strike Fighter Squadron 102 (VFA-102), Diamondbacks, Naval Air Station (NAS) Atsugi, Japan (JPN), breaks the sound barrier during a fly-by over the aircraft carrier USS KITTY HAWK (CV 63). Camera Operator: PH3 JONATHAN CHANDLER, USN. Image The taken by U.S. Navy, taken or made during the course of the person's official duties. As a work of the U.S. federal government, the image is in the public domain.

The second image to the right shows countermeasure flares.  

Finally, we see to the left below an image of a contrail.

Here a DC-8 Airborne Laboratory is in flight during research mission. The view from above shows the contrail. Dated February 1999 This is a NASA Photo by: Jim Ross. The image is in public domain because it was created by NASA.

Some contrails last only seconds in the sky. Other contrails will remain in the sky for hours. This duration depends on different elements such as wind condition.

Image was taken by a USAF Captain who flew C-130s. The Aircraft type is a Lockheed C-130 Hercules.

Wind may drag a contrail away and disperse the cloud. Certain contrails can be used to determine not only type of aircraft, but its direction, speed, manoeuvre and even more “intimate” details.

Civilian flights across the globe raise to meet the demand of tourists and travelers. Every day, there are more and more airplanes in the sky and more airplane routes. This has caused people to pay close attention to the sudden appearence of contrails. More planes obviously mean more contrails.

Contrails will change colors when the sun comes down. They will be altered by sunrise, winds, storms, and other weather patterns. For example, a contrail by a water port will tend to be more clear but the clarity and shape will also depend on the aircraft, its course and route of travel. The wide range of variations of contrails has led to massive international speculation, rumors, and conspiracy theories.

One of the most interesting conspiracy theories about contrails is probably the Chemtrail Conspiracy. According to various conspiracy theoretical sources, some contrails are actually chemicals or biological agents deliberately sprayed at high altitutdes for a purpose undisclosed to the general public. Radio talk shows, blogs, and other sources of information discuss such theories with great passion.

The Federal Agencies have received thousands of complaints from people who have demanded an explanation. Although scientists and government agencies repeatedly deny the Chemtrail Conspiracy theory, enthusiastic observers continue to show their case.

So what is the source of contrails? Are all contrails the same? Why do some appear to be different?

If we observe certain contrails we will notice a change of color. Colors in the contrails may be different from the colors of the clouds as the sun sets. This can occur due to the temperatures and the properties of condensation. In other words, the condensation of the clouds is different from the condensation of the contrails, therefore when the UV light hits the molecules of the contrails and of the clouds, different colors arise.

If we look closely at some contrails we notice that not all contrails draw a straight line. As the aircraft flies through the sky, the contrail forms following its route. Why is the contrail then not always a straight line? A contrail sometimes zigzags randomly followed by a curve.

(The Sun Maker)

This can be, as explained before, due to wind or the change in the aircraft’s route. However other contrails suddenly zigzag to later rearrange its course. The result is a line with some noticeable disturbances. When a planes flies by the contrails are not very noticeable but as the wind and clouds eventually start to disperse into the air the lines can be seen in zigzags or a straight line.

This article dismisses the notion of a ‘Chemtrail conspiracy’. As we can observe from various photos, chemical in contrails are used mainly for agricultural projects and are very distinct from normal contrails.

Contrail at Buenos Aires Port, Argentina. (The Sun Maker)

Yet, why are some contrails evidently non-linear? To answer this, it may be basic noise pollution or rather the acoustic fatigue as a possible source of contrail formation. Acoustic fatigue is quite scary.

Basically, acoustic fatigue is the vibration of an object under stress. If an object gives off such vibration, it’s a sign that the object or structure will collapse. So, are contrails signs of acoustic fatigue?